Medical carbon monoxide delivery system

ABSTRACT

A medical carbon monoxide generator provides for a solid carbon material that may be heated at substantially normal atmospheric pressure to provide a source of medical quality carbon monoxide. The heating source may be an electrical filament or laser controllable by a microcontroller to provide accurate delivery rates and amounts. In one embodiment, a replaceable cartridge holding the carbon material may be used.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

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CROSS REFERENCE TO RELATED APPLICATION

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BACKGROUND OF THE INVENTION

The present invention relates to medical gas generators and inparticular to a device for producing medical purity carbon monoxide fortherapeutic purposes.

Carbon monoxide is a colorless and odorless gas that is frequently abyproduct of combustion and which can be toxic to humans in highconcentrations. In lower concentrations, however, recent research hassuggested that carbon monoxide can have efficiency in bio protective andanti-inflammatory applications. In such situations, low concentrationsof carbon monoxide may provide therapies for cardiovascular disease andcancer treatment, aid in organ preservation and in preventing acute andchronic rejection of transplanted organs, and may help in the treatmentof acute lung and kidney injury or in cases of sepsis and shock.

Medical grade carbon monoxide is available in pressurized cylinders frommedical gas providers. Carbon monoxide is an odorless and colorlesstoxic and flammable gas. Pressurized cylinders are naturally heavy anddifficult to manage. All pressurized cylinders possess inherent andunavoidable safety issues including the risk of asphyxiation and ofexplosive rupture of the tank. The toxic and flammable properties ofcarbon monoxide engenders additional risk as even a relatively slow, anddifficult to detect, leak could have catastrophic consequences in anuncontrolled environment. These risks lead to a general desire tominimize the presence of pressurized cylinders, particularly of toxicand flammable gases, in many situations including public transport, allflying vehicles (airplanes and helicopters), and in-home care. Thispresents a significant problem in the use of carbon monoxide for many ofthe possible indications including organ preservation, at least to theextent that such organs are often transported in a helicopters and otheraircraft on a rush basis.

SUMMARY OF THE INVENTION

The present invention provides a carbon monoxide generator for medicaluse that operates substantially at standard atmospheric pressure. Thegenerator produces carbon monoxide from a solid carbon source that isheated on demand to specific temperatures to generate a desired carbonmonoxide stream. A control system provides both versatile delivery andmonitoring of the stream for safety. Eliminating the need for apressurized bottle of carbon monoxide allows the generator to beportable and generally allowable in many situations in which pressurizedcylinders are problematic

Specifically then, in one embodiment, the invention provides a medicalcarbon monoxide generator having a reaction chamber holding a purifiedcarbon element and providing an ingress port and egress port. A pumpcommunicates with the ingress port to provide a source of air passinginto the reaction chamber and out of the egress port and within thereaction chamber an electrically controllable heater element heats thepurified carbon element in the presence of the air to generate carbonmonoxide gas from the reaction of the heated purified carbon with theair of the reaction chamber. A sensor system monitors carbon monoxidepassing out the egress port and provides a signal to an electroniccontroller to control the electrically controllable heater in responsethereto. The carbon monoxide is delivered to a respiratory deliveryappliance through the egress port to provide carbon monoxide to apatient for respiration thereof.

It is thus a feature of at least one embodiment of the invention toprovide a convenient source of medical carbon monoxide eliminating theneed for pressurized gas bottles.

The purified carbon element may be at least USP grade pure carbon andmay be of a limited volume to prevent generation of enough carbonmonoxide to present either a toxicological or flammability risk in evena relatively small enclosure.

It is thus a feature of at least one embodiment of the invention toprovide medically pure carbon monoxide by employing a pure solid carbonprecursor eliminating the need for substantial filtration orpurification of the resulting gas flow.

The sensor system may include a flow sensor measuring flow from theegress port and at least one carbon monoxide concentration sensor.

It is thus a feature of at least one embodiment of the invention toprovide close loop control for precise and accurate delivery of apotentially toxic gas.

The electronic controller may control the electrically controllableheater element to provide a predetermined time varying change in carbonmonoxide delivered to the respiratory delivery appliance.

It is thus a feature of at least one embodiment of the invention topermit complex treatment schedules without the need for high pressuremetering valves or the like or a venting of excess carbon monoxide.

The electrically controllable heater element may be an ohmic resistor inthermal communication with the purified carbon element.

It is thus a feature of at least one embodiment of the invention toprovide a simple and low-cost method of generating carbon monoxide incontrolled quantities.

Alternatively, the electrically controllable heater element may be anoptical radiation source focused on the purified carbon element, forexample, a laser.

It is thus a feature of at least one embodiment of the invention toprovide for extremely high-speed temperature control possible withlocalized optical heating for precise carbon monoxide metering.

The sensor system may include redundant carbon monoxide sensors and theelectronic controller may use readings from the carbon monoxide sensorsto deduce carbon monoxide concentration in the egress port.

It is thus a feature of at least one embodiment of the invention toprovide for a high degree of safety commensurate with possible toxicityand flammability of carbon monoxide.

The electronic controller may record a time record of carbon monoxidedelivery through the egress port.

It is thus a feature of at least one embodiment of the invention toprovide for precise record-keeping of the treatment for verification ofthe treatment plan and monitoring proper operation of the generator.

The electronic controller may determine a total amount of carbonmonoxide generated in the reaction chamber during operation of themedical carbon monoxide generator.

It is thus a feature of at least one embodiment of the invention topermit treatment monitoring and control according to total carbonmonoxide delivery.

The reaction chamber may be in a cartridge releasably connectable to atleast one of the fan and sensor system.

It is thus a feature of at least one embodiment of the invention toprovide a convenient method of replacing the carbon source for reliableand consistent behavior.

It is thus a feature of at least one embodiment that the carbon sourcebe of limited volume such that a “worst case scenario” cannot generateenough carbon monoxide to create a hazard in most environments.

The cartridge may include a data communication element communicatingwith a remainder of the medical carbon monoxide generator system toidentify the cartridge for controlling operation of the medical carbonmonoxide generator.

It is thus a feature of at least one embodiment of the invention topermit treatment protocols to be implemented by selection of the propercartridge without the need for complex programming of the generator bythe user.

The electronic controller may control the electric heater according tothe identification of the cartridge to provide at least one of apredetermined schedule of carbon monoxide delivery from the cartridgeand a predetermined total production of carbon monoxide from thecartridge.

It is thus a feature of at least one embodiment of the invention toensure proper operation of the cartridge by monitoring its use andpossible exhaustion.

The data communication element may include a memory for storing usagedata with respect to the reaction chamber.

It is thus a feature of at least one embodiment of the invention toensure spent cartridges are not reused regardless of the device withwhich they are associated.

The medical carbon monoxide generator may further include a filterfiltering the air received by the fan.

It is thus a feature of at least one embodiment of the invention toprovide a system that may work with atmospheric pressure air from theroom or the like.

One embodiment the invention may provide an organ transplant containersystem having an insulated container for receiving a transplant organheld in a storage liquid and a carbon monoxide generator attached to theinsulated container and communicating with the storage liquid to providea source of carbon monoxide to the storage liquid by heating a carbonsource in atmospheric air.

It is thus a feature of at least one embodiment of the invention toprovide a system for preserving transplant organs during transportationcompatible with high-speed air transport by helicopter or the like.

The organ transplant container may include a scrubber elementcommunicating with the storage liquid to vent gas from the storageliquid into the scrubber element and to scrub carbon monoxide from thevented gas.

It is thus a feature of at least one embodiment of the invention toprovide a system that may be used in a closed environment such as acockpit without concern about excess carbon monoxide levelsaccumulating.

These particular features and advantages may apply to only someembodiments falling within the claims and thus do not define the scopeof the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a first embodiment of the carbonmonoxide generator of the present invention as may be used with arespiratory appliance for delivery of carbon monoxide to a patient'srespiratory tract;

FIG. 2 is a block diagram of the generator of FIG. 1 showing a cartridgebased filament system in which an electrical filament is heated in theproximity of purified carbon to generate carbon monoxide in the controlloop as controlled by sensors;

FIG. 3 is a figure similar to that of FIG. 2 showing an alternativecartridge design employing a laser for heating of the carbon material toproduce carbon monoxide;

FIG. 4 is a chart showing an example predetermined delivery schedulethat may be implemented with the present invention together withmonitoring data that may be logged and tracked for safety purposes;

FIG. 5 is a cross-sectional view of an organ transplant containeremploying the medical carbon monoxide generator of the present inventionproviding both a source of carbon monoxide to an organ pouch and thescrubbing of excess carbon monoxide recovered from that pouch; and

FIG. 6 is a block diagram of the generator of FIG. 5 showing the variouscomponents thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIG. 1, a medical carbon monoxide generator system 10,may include a generator unit 12 communicating with a delivery appliance14 such as a nasal cannula 16 or a face mask 18 of a type that maydeliver gases to a patient's respiratory tract such as are generallyunderstood in the art.

The generator unit 12 may be a portable device having a housing 20transported by use of the handle 21 or the like extending upward fromthe housing 20. One sidewall 22 of the housing 20 may provide for areleasable tubing connector 24 for attachment to flexible tubing 26 ofthe delivery appliance 14 (the latter of which may be disposable) and inparticular for communicating with flexible tubing 26 leading to eitherthe nasal cannula 16 or the face mask 18.

A front wall 28 of the housing 20 may provide for a socket 30 that mayreceive a replaceable cartridge 32 as will be described in furtherdetail below as held by mechanical snap elements or the like. An uppersurface 33 of the housing 20 may provide for a user interface 35, forexample, including an LCD display and membrane or other type pushbuttonsfor user control of the medical carbon monoxide generator system 10.Power for the generator system 10 may be provided, for example, by aline cord 36 or by internal battery systems, or both.

Referring now also to FIG. 2 the generator unit 12 may incorporate anelectric fan 40 or similar blower or pump receiving air from an airfilter 42, for example a HEPA filter suitable for removing dust, moldand allergens from room air. The air filter 42 may further includeactivated carbon filtration or the like for odor and volatilereductions. Generally, the generator unit 12 may thus operate atstandard atmospheric pressures with standard room air without the needfor bottled or compressed gas. An outlet of the fan 40 may pass to aport 43 in the side of the socket 30 that may engage with thecorresponding port 44 in one side of the cartridge 32 when the cartridge32 is in place within the socket 30. An air stream from the fan 40through port 43 and port 44 may pass through the cartridge 32 to an exitport 46 in the cartridge 32 that connects to port 48 of the generatorunit 12 when the cartridge 32 is in the socket 30. One or both of theports 44 and 46 operate in conjunction with the fan 40 to limit theoxygen in the cartridge 32 favoring the production of CO over CO₂.

A resistive filament 50 may be positioned in the air stream within thecartridge 32, and may be coated with or proximate to a purified carbonmaterial 52, for example, having a USP medical grade meeting orexceeding requirements of the US Pharmacopeia. In one embodiment, thispurified carbon material 52 may be elemental carbon or elemental carboncompounded with a binder material with low volatility and reactivity.The resistive filament 50 provides ohmic resistance to produce a desiredand predetermined heating as a function of current introduced throughthe resistive filament 50 as may be controlled, for example, by acontrolled current source of a type known in the art. Desirably, theresistive filament 50 is operated to provide temperatures of 600 C ormore that favor CO production in a limited oxygen environment enforcedby the operation of the fan 40.

Generally, the amount of purified carbon material 52 may be limited toapproximately an amount needed for a particular medical procedure andthe cartridges 32 may be identified to a particular medical procedure inthis regard as will be discussed below. The resistive filament 50 mayextend longitudinally along the axis of airflow within insulating walls54 sized to allow airflow outside of the carbon material 52 within thewalls 54. Ends of the resistive filament 50 may communicate byreleasable electrical connectors 56 to a controller 58 within thehousing 20 of the generator unit 12. A thermal sensor 57 may also beattached to the carbon material 52 to provide a reading of temperatureof the carbon material 52 during heating and may communicate throughsimilar connectors 56 with the controller 58.

As will be discussed in greater detail below, an electrical currentproduced and controlled by the controller 58 may heat the filament 50 tocause heating of the carbon material 52 to a degree as to generatecarbon monoxide 53 in reaction with oxygen in the air passing over thefilament. In this regard, the cartridge 32 provides a replaceablereaction chamber for generating carbon monoxide.

Carbon monoxide gas exiting port 46 through port 48 may pass into asensor chamber 60 holding redundant carbon monoxide sensors 62 and aflow sensor 64. The sensor chamber 60 connects at an outlet to connector24 communicating with tubing 26 of appliance 14. Each of the carbonmonoxide sensors 62 and flow sensor 64 may provide an input signal tothe controller 58 and the controller 58 may provide an output signalcontrolling the fan 40. In this way, the controller 58 may effect aclosed loop control algorithm to control the concentration and totalvolume of carbon monoxide delivered into the appliance 14 in accordancewith control signals received from the control interface 35 and mayconfirm operation on the same control interface 35. A deliveryconcentration (mg CO/hour) may be entered into the control interface 35or a concentration per body weight per hour and body weight entered intothe control interface 35. In this latter case, the entered value may becompared against a safe maximum of 3 mg of CO per kg of patient bodyweight per hour to provide an override or alarm, if necessary.

In one embodiment, a cleanup filter 25 may be placed in series with thetubing 26 to the appliance 14, providing a filtration of particulatematter and possibly a chemical filter to remove undesired combustionbyproducts such as nitrogen oxides or volatile materials.

For purposes of control, the controller 58 may generally include acomputer processor 66 executing a stored program 68 held in memory 70.The stored program 68 may provide, for example, one or more schedules ofcarbon monoxide delivery (as will be discussed below) noting a series ofconcentrations and durations over time as implemented by an internalclock of the processor 66. The concentrations of the schedules may beimplemented by control of the fan 40 and/or current to the filament 50according to feedback signals received from the thermal sensor 57, thecarbon monoxide sensors 62 and the flow sensor 64 using standardfeedback techniques, for example, by implementing one or more PID typealgorithms, for example, operating temperature control loops and flowcontrol loops. The scheduling process will be described in greaterdetail below.

Referring now to FIG. 3, in an alternative embodiment of the cartridge32, the cartridge 32 may provide for an insulating support 80 within thecartridge 32 supporting a purified carbon sheet 82 (of similar carbonmaterial 52 described above) opposite an optical port 84 along an axis86 generally perpendicular to the flow of air within the cartridge 32between ports 44 and 46. A solid-state laser 87 positioned within thehousing 20 may direct a beam of light along axis 86 to provide intensesurface heating of the carbon sheet 82 producing a stream of carbonmonoxide 53 to be controlled and conducted to the appliance 14 in themanner described above with respect to the filament 50. In oneembodiment, a mechanism to scan the laser beam with respect to thecarbon sheet 82 may be provided to ensure a fresh surface. Accuratecontrol of the amount of carbon monoxide 53 generated may be provided bythe duty cycle modulation of the laser 87 as part of a control feedbackloop in conjunction with the sensors and fan described above, however,in this case with the controller 58 controlling operation of the laser87 as opposed to current flow through a filament. The laser desirablyoperates to rapidly elevate the carbon sheet 82 to above 600 C in asmall area that will be oxygen limited.

In both of the embodiments described with respect to FIG. 2 and FIG. 3,the cartridge 32 may provide for an identifying tag 90 such as an RFIDtag or barcode or the like that may be read by a reader 92 held withinthe housing 20 adjacent to the tag 90 when the cartridge 32 is withinthe socket 30. This identifying tag 90 may be “read-only” (as with theexample of a barcode) or may provide for limited writable data storage.In both cases, the tag 90 may uniquely identify the cartridge 32, forexample with a serial number, and may identify the cartridge 32 to aparticular medical procedure, for example, appropriate for the amount ofcarbon material within the cartridge. This latter information may beused to guide the protocol implemented by the controller 58 by aconnection between the reader 92 and the controller 58. In one example,this information may provide a particular schedule for the delivery ofcarbon monoxide including concentrations with respect to time (e.g., COmg/kg of patient weight/hr or CO mg/hr) or total delivery (e.g. 100 mgfor a single use cartridge intended for use for an hour or 1-2 grams fora multi use cartridge). It will be understood that the necessaryinformation for this purpose may be stored directly on the tag 90 or thetag may provide an index to a separate storage of this information inthe memory 70 of the controller 58. Use of the cartridge 32 toeffectively program the generator unit 12, eliminates the need forcomplex programming of the generator unit 12, for example, through theuser interface 35. In the case where the tag 90 may receive and storedata, stored data may be used to designate a rated life of the cartridgethat remains and prevent inadvertent reuse of spent cartridges 32. Inone system, the remaining life of the cartridge 32 may be stored on thetag 90. Alternatively the remaining life may be stored in memory 70linked to a unique serial number of a cartridge 32 provided by tag 90,and the remaining life may be checked prior to use of a cartridge 32.

In some embodiments, the controller 58 may communicate with the datarecorder device 96, for example a thermal printer, that may logmeasurements made by the carbon monoxide sensors 62 and flow sensor 64to confirm a particular medical treatment. The data recorder device 96may alternatively be a memory storage device such as a flash memory orother memory type and may communicate with the controller 58 either bydirect electrical connection through a connector or wirelessly or thelike as is understood in the art.

In an alternative embodiment, the cartridges 32 may be designed tooperate open loop using a known strength of the laser 87 or electricalcurrent provided to the filament 50 and known restricted airflow controlby the fan 42 to favor the production of CO over CO₂. To the extent thatthis open loop preference can only be ensured for limited period of time(for example with a pristine carbon source receiving the laser beam 86or operation with a relatively fresh coating of carbon material 52 onthe filament 50) the cartridge 32 may be programmed to requirereplacement by the operator after this period of time has been exhaustedbefore the carbon source is exhausted.

Referring now to FIG. 4, the generator unit 12 may operate to implementa stored protocol 98 providing a schedule of carbon monoxide delivery(for example concentration and/or flow rate delivered to the appliance14) as a function to time. For example, as depicted, an initial highconcentration amount may be delivered followed by a lower steady stateconcentration amount ultimately terminating at a predetermined time. Thedepicted schedule assumes a constant flow rate; however, this is notrequired. Delivery may begin when the generator unit 12 is activated bya user through the user interface 35 and may proceed as monitored by thesensors 62 and 74. In one embodiment, readings from the sensors 62 arecompared and averaged so long as the difference between the carbonmonoxide sensors 62 is less than a predetermined threshold amount. Adifference beyond this threshold amount, such as may indicate a failureof a carbon monoxide sensor 62, may stop operation of the generator ofunit 12 in production of carbon monoxide and provide an alarm to theuser through user interface 35. In such cases, fan 40 may remain on toprovide a purging of excess carbon monoxide from the appliance 14.Audible or visual alarms may then be provided on the user interface 35and alarm signals may be transmitted, for example, wirelessly to remotemonitoring devices.

The readings of the carbon monoxide sensors 62 and flow sensor 64 may betracked and stored to provide actual delivery schedule 99 which willgenerally conform closely to the stored protocol 98 or the close loopcontrol affected by the controller 58. Deviation between these twocurves of actual delivery schedule 99 and a stored protocol 98 may beused to provide for an alarm condition indicating possible equipmentmalfunction, again through user interface 35, and again may stopgeneration of carbon monoxide. The information of delivery schedule 99may be provided to the data recorder device 96 as discussed above orrecording.

Total carbon monoxide delivery 100 may also be tracked by calculatingthe integral of the actual delivery schedule 99 weighted by a flow ratefrom flow sensor 64. This total carbon monoxide delivery 100 may be usedto determine the lifetime of the cartridge 32. Alternatively, a simplylapsed time of use of the cartridge 32 may be employed. Either theactual delivery schedule 99 or total carbon monoxide delivery 100 may becompared against an alarm limit 102 to provide an indication of possibleproblems with the delivery procedure that may trigger a shutdown of thegenerator unit 12 and suitable alarms.

Referring now to FIGS. 5 and 6, in an alternate embodiment, thegenerator unit 12 part of an organ carrier system 120 may provide, forexample, an insulated watertight container 122 having a base wall 124and upstanding sidewalls 126 constructed of expanded polymer foam withina plastic shell. An insulated lid 128 may attach at the top of theupstanding sidewalls 126 to provide an enclosed insulated volume thatmay receive a transplant organ 130, for example, sealed in a plasticpouch 132 together with a preservation fluid 140 of a type known in theart and typically selected for the type of organ. The generator unit 12may attach to one upstanding sidewall 126 and connector 24 of thegenerator unit 12 may attach to a carbon monoxide delivery line 134threaded out of an opening in the sidewall 126 from the pouch 132. Atthe pouch 132, the delivery line 134 may be welded to a pass-throughflange 136 of the pouch 132 to provide a conduit into the pouch 132leading to a diffusion element 138 providing for a of bubbling carbonmonoxide 53 through a transplant organ preservation fluid 140 duringtransport of the organ 130. A monoxide return line 142 may attach to asimilar pass-through flange 144 positioned near the top of the pouch 132and attached within the pouch 132 to a liquid filter 146 resisting inflow of liquid to return excess gaseous carbon monoxide to the generatorunit 12 at a connector 150 on cartridge 32.

Referring specifically to FIG. 6, cartridge 32, in this embodiment, mayincorporate the intake filter 42 described above. The intake filter 42provides input air through a port interface 152 between the cartridge 32and the housing 20 as drawn by the fan 40. Fan 40, in turn, may returnthis air to the cartridge 32 through a second port interface 154 to bereceived within a reaction chamber of the cartridge 32 being of thedesigns described above with respect to FIG. 2 or FIG. 3. The reactionchamber outflow may pass through a third port interface 156 back intothe housing 20 to be received by the sensor chamber 60 described asabove, ultimately to be communicated to connector 24 and from there tothe respiratory appliance 14 (not shown).

In this embodiment, the cartridge 32 may also include a scrubber element160 receiving excess carbon monoxide through connector 150 from returnline 142 to reduce carbon monoxide discharged into the atmosphere. Inthis design, the consumable filter 42 and scrubber element 160 may thusbe replaced with the cartridge 32 to ensure their freshness.

In order to promote portability in the movement of organ carrier system120 for transporting the organ 130, a battery pack 162 may be includedwithin the housing 20 which provides for short-term energy storagenecessary for organ transportation.

It will be generally appreciated that the fan 40 may be located eitherupstream or downstream from the reaction chamber provided by thecartridge 32. Generally, the fan is not limited to propeller typedesigns but may be any kind of air pump including blowers, bellows,ionic pumps and the like. Other sources of heat beyond the laser andfilament are also contemplated including non-coherent light sources suchas flash tubes or LED arrays, or microwave and radiofrequency energy,and the like.

Certain terminology is used herein for purposes of reference only, andthus is not intended to be limiting. For example, terms such as “upper”,“lower”, “above”, and “below” refer to directions in the drawings towhich reference is made. Terms such as “front”, “back”, “rear”, “bottom”and “side”, describe the orientation of portions of the component withina consistent but arbitrary frame of reference which is made clear byreference to the text and the associated drawings describing thecomponent under discussion. Such terminology may include the wordsspecifically mentioned above, derivatives thereof, and words of similarimport. Similarly, the terms “first”, “second” and other such numericalterms referring to structures do not imply a sequence or order unlessclearly indicated by the context.

When introducing elements or features of the present disclosure and theexemplary embodiments, the articles “a”, “an”, “the” and “said” areintended to mean that there are one or more of such elements orfeatures. The terms “comprising”, “including” and “having” are intendedto be inclusive and mean that there may be additional elements orfeatures other than those specifically noted. It is further to beunderstood that the method steps, processes, and operations describedherein are not to be construed as necessarily requiring theirperformance in the particular order discussed or illustrated, unlessspecifically identified as an order of performance. It is also to beunderstood that additional or alternative steps may be employed.

References to a processor, can be understood to include one or moremicroprocessors that can communicate in a stand-alone and/or adistributed environment(s), and can thus be configured to communicatevia wired or wireless communications with other processors, where suchone or more processor can be configured to operate on one or moreprocessor-controlled devices that can be similar or different devices.Furthermore, references to memory, unless otherwise specified, caninclude one or more processor-readable and accessible memory elementsand/or components that can be internal to the processor-controlleddevice, external to the processor-controlled device, and can be accessedvia a wired or wireless network.

It is specifically intended that the present invention not be limited tothe embodiments and illustrations contained herein and the claims shouldbe understood to include modified forms of those embodiments includingportions of the embodiments and combinations of elements of differentembodiments as come within the scope of the following claims. All of thepublications described herein, including patents and non-patentpublications are hereby incorporated herein by reference in theirentireties.

What we claim is:
 1. A medical carbon monoxide generator comprising: areaction chamber holding a solid purified carbon element and providingan ingress port and egress port; a pump communicating with the ingressport to provide a source of air passing into the reaction chamber andout of the egress port; an electrically controllable heater elementheating the purified carbon element in the presence of the air togenerate carbon monoxide gas from the reaction of the heated purifiedcarbon with oxygen in the air of the reaction chamber, the production ofcarbon monoxide consuming oxygen in the reaction chamber; a respiratorydelivery appliance communicating with the egress port to provide carbonmonoxide to a patient for respiration thereof; and a controllercommunicating with the electrically controllable heater element and thepump and executing a stored program held in a non-transient medium tocontrol the same to produce medical purity carbon monoxide forrespiration by a human being from the purified carbon element, whereinthe pump, ingress port, heater element, and egress port operatingtogether are adapted to limit oxygen from air introduced in the reactionchamber during operation of the heater to favor the production of carbonmonoxide over carbon dioxide during the heating of the purified carbonelement.
 2. The medical carbon monoxide generator of claim 1 wherein thepurified carbon element is at least USP grade pure carbon.
 3. Themedical carbon monoxide generator of claim 1 wherein the electricallycontrollable heater element is an ohmic resistor in thermalcommunication with the purified carbon element.
 4. The medical carbonmonoxide generator of claim 1 wherein the electrically controllableheater element is an optical radiation source focused on the purifiedcarbon element.
 5. The medical carbon monoxide generator of claim 4wherein the optical radiation source is a solid-state laser.
 6. Themedical carbon monoxide generator of claim 1 further including a sensorsystem for monitoring at least one of gas flow through the reactionchamber and carbon monoxide concentration of gas passing out of theegress port; and wherein the electronic controller receives a signalfrom the sensor system to control the electrically controllable heaterin response thereto.
 7. The medical carbon monoxide generator of claim 6wherein the electronic controller controls the electrically controllableheater element to provide a predetermined time varying change in carbonmonoxide delivered to the respiratory delivery appliance.
 8. The medicalcarbon monoxide generator of claim 6 wherein the electronic controllerfurther records a time record of carbon monoxide delivery through theegress port.
 9. The medical carbon monoxide generator of claim 6 whereinthe electronic controller determines a total amount of carbon monoxidegenerated in the reaction chamber during operation of the medical carbonmonoxide generator.
 10. The medical carbon monoxide generator of claim 6further including redundant carbon monoxide sensors and wherein theelectronic controller uses readings from the carbon monoxide sensors todeduce carbon monoxide concentration in the egress port.
 11. The medicalcarbon monoxide generator of claim 1 wherein the reaction chamber is ina cartridge releasably connectable to at least one of the pump andsensor system.
 12. The medical carbon monoxide generator of claim 11wherein the cartridge includes a data communication elementcommunicating with a remainder of the medical carbon monoxide generatorsystem to identify the cartridge for controlling operation of themedical carbon monoxide generator.
 13. The medical carbon monoxidegenerator of claim 12 wherein the electrically controllable heateraccording to the identification of the cartridge provides least one of apredetermined schedule of carbon monoxide delivery from the cartridgeand a predetermined total production of carbon monoxide from thecartridge.
 14. The medical carbon monoxide generator of claim 12 whereinthe data communication element includes a memory for storing usage datawith respect to the reaction chamber.
 15. The medical carbon monoxidegenerator of claim 1 further including a filter filtering the airreceived by the pump.
 16. The medical carbon monoxide generator of claim1 further including a filter filtering the carbon monoxide received fromthe reaction chamber.